1. Field of the Invention
The present invention relates to inflatable dual wall structures and, more particularly, of the type utilized to form roof structures and other lightweight, large span, open structures.
2. Description of the Prior Art
Large span tent-like structures are widely used in flea markets, fairs, receptions, exhibitions and the like. Such applications necessitate a structure that is easily erected and taken down and that is economic and safe. Large canvas tents held in place by a series of masts and multi-directional poles are well known. On the other hand, the erection of such canvas tents is somewhat laborious.
Also known in the art are double wall inflatable structures made of lightweight fabric or synthetic material. These pneumatic structures generally include a complicated internal structure that can be made up of a plurality of intersecting rods or poles. Other inflatable pneumatic structures, such as the one disclosed in U.S. Pat. No. 4,676,032 (issued to Jutras on June 30, 1987) comprise a self-supporting inflatable structure including a polyhedron frame made from tension cables interconnected and joining at nodes with an envelope surrounding the frame. Anchoring skirts extend from each node line to predetermined lines on the panels forming the envelope. Under sufficient air pressure inside the envelope, the same produces an arch-shaped roof, wherein all of the tension cables are under tension and the overall structure becomes rigid, stable and capable of resisting deformation caused by various external forces applied thereto.
Although the above described inflatable structure yields excellent results, there is a need for an inflatable structure of different design and using generally different principles in order to obtain a structure of simple construction and requiring very few on-site steps for its erection.